Howto: Capture and decode FlexRay traffic using Pico oscilloscope - nanamiwang/openpilot GitHub Wiki

  • Connect the oscilloscope to PC via USB cable.
  • Launch PicoScope6 software.
  • Add more hardware buffers so that more FlexRay frames can be captured.
    • From "Tool" menu, open "Preferences" dialogue, set "Maximum Waveforms" to a big number, for Pico 2204A, the maximum value is 5000.
  • From "View" menu, click "View Properties" button to open the properties window. This will shown the current sample rate on scope. For FlexRay decoding, the sample rate should be at least 50MS/s. If it shows e. g. a lower value like 25 Mbps then you need to know that you can't change the sample rate in this view. It is being influenced by timebase controls (collection time). Don't worry we will get later on that.
  • Connect the scope to the BP or BM port on FlexRay bus via a high speed probe.
    • Connect the BNC header of the probe to channel A port on the scope.
    • Connect the other side of the probe to the BP or BM port on FlexRay bus, connect the scissor to a reliable ground point.
  • Start capturing. Wait until the waveform of FlexRay frames can be seen in waveform window.
  • Enable FlexRay frame decoding.
    • From "Tool" menu, open "Serial Decoding" dialogue.
    • Click "Create" button, add a FlexRay decoder.
      • Choose Channel A
      • The threshold should be auto detected, if not, set it to 2.0v
      • Set baud rate t0 10Mbps.
    • Enable the decoder.
    • The "Serial Decoding" window will be shown at the below of main window.
  • Change "Collection Time" until there are FlexRay frames decoded successfully in "Serial Decoding" window. For Pico 2204A, collection time has to be set to 10μs/div, the sample rate is 50MS/s.
  • Wait until there are enough frames have been gathered into the waveform buffers. The current used number of buffer is shown on the toolbar.
  • Stop capture.
  • Disconnect the probe from FlexRay bus.
  • In "Serial Decoder" window,
    • Change "Current Buffer" to "All Buffers", so that we can see all the captured FlexRay frames.
    • Click "Filter" button to enable filter, enter "1" into Frame CRC value, so that frames with incorrect CRC can be filtered out.
  • Save the waveform to .pdata file, so that the waveforms can be replayed and shared with others.